The present invention relates to an electric fan having a grille including a multiplicity of inclined grille plates for deflecting the flow of air generated by the fan. The electric fan of the invention can suitably be used as a floor or desk-top type fan, wall-hung type fan or as a ventilation fan mounted in a window to induce fresh outdoor air into the room.
Such an electric fan has been proposed as having means for changing the direction of air flow in relation to time, in order to attain a pleasant flow of air well resembling natural wind.
A typical example of such an electric fan is the so-called oscillation type electric fan in which an electric motor, to which a fan blade unit is connected directly, is oscillated in a horizontal plane to change the direction of flow of air in relation to time. Another example of such an electric fan is the so-called rotary grille type fan in which a rotary grille having a number of grille plates is rotated at a low speed, while the direction of the motor is kept unchanged, to change the direction of flow of air in relation to time. The latter type of electric fan is disclosed, for example, in the U.S. Pat. No. 4,123,197.
The oscillation type electric fan, however, has various drawbacks. Namely, the direction of flow of air can be changed only horizontally, because the motor oscillates only in a horizontal plate. In addition, since a complicated link mechanism is required for the oscillatory motion of the motor, the electric fan is difficult to produce and is susceptible to a malfunctioning of the link mechanism.
The rotary grille type electric fan has an extremely simple construction because the rotary grille is rotated at a low speed simply by a small-sized electric motor. This type of electric fan, however, has a disadvantage that the flow of air is directed also to the area where there is no person who would receive and benefit from the air flow.